Working on the standard library in VScode

[jurgenvinju]

I would like a special mode, or configuration option in VScode for
working on the standard library.

Currently the rascal project is configured for working on the compiler or the tutor, since you always
need a stable, previously released, stdlib for that. The standard lib is not on the source path and the
other code is.

A "reversed" mode where the other code is not on the source path but the standard library is can
only work if the builtins in Java are not changed. If you do want to edit library code that changes builtins, you should start your own RascalShell in debug mode and work with that.

But for the formatter and parser generator and other larger projects hidden in the stdlib it would be nice to have a:

• terminal REPL with the correct source path
• type-checker configured correctly
• working interactive debugger.
• nice warnings/errors if you accidentally modify a builtin.

@rodinaarssen do you have thoughts on this?

[DavyLandman]

A "reversed" mode where the other code is not on the source path but the standard library is can only work if the builtins in Java are not changed. If you do want to edit library code that changes builtins, you should start your own RascalShell in debug mode and work with that.

When we originally moved to the new mode of using maven, we made a version with exactly this assumption (in PR #2112). But we reverted that as it lead to many confusing issues. Specifically during this PR this got reverted: #2181 (in commit 475053a)

However, all the work we're doing with the disconnecting VS Code from rascal repl, it might be possible to start the REPL from the java, and connect it to the VS Code APIs. As all the special features are getting more and more replaced by json rpc. the last one is the #2641. But that would mean you get the same mode we have with starting RascalShell as a java process, except that it will behave like the normal rascal terminal with all the integration. So no special handling needed for buildins etc.